EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...
EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ... EFFICACY OF TEMPORARY FIXED RETENTION FOLLOWING ...
Total chin, which is mostly a soft tissue measurement but does include a portion of the bony chin, also was significant (P = 0.01). Total chin was greater at pretreatment (Figure 4-6) in the fixed group, although there was barely a millimeter difference between the two groups (14.74 and 13.67 mm). It is not likely that these differences at the pretreatment examination governed the orthodontist’s decision concerning whether to use fixed retention at the end of treatment, but they do suggest that some occlusal conditions may influence the decision. It also is likely (Table A-1) that these differences evaluated at the start of treatment carried through to affect the posttreatment status—and that this latter condition controlled the decision about kind of retention. More of the variables (7 denoted with an asterisk) were significantly different at the end of treatment (Table A-2). This in and of itself might indicate that orthodontists were attuned to which cases warranted fixed retention. Of note, incisor depth and overjet, which were significant at the pretreatment examination, persisted as significant predictor variables at the end of treatment. Incisor depth and overjet had been reduced in both groups during treatment, yet remained significantly greater in the fixed group at the end of treatment. Total chin also continued to be statistically significant between groups at the end of treatment (P = 0.02). The fixed retention group maintained a greater average value of 16.4 mm versus 15.4 mm in the removable group. Incisor irregularity, which intuitively can be regarded as a proximate reason for using a fixed appliance, was greater in those receiving a fixed appliance (Figure 4-7), though the difference between the means seems small (0.5 mm and 0.2 mm). Even though the mean difference was small, this difference is statistically significant. Those receiving a fixed retainer were more likely to exhibit greater Incisor Irregularity at the end of treatment. Overbite also was significantly larger in the fixed group at the posttreatment examination. Table A-2 lists the Curve of Spee and reveals that the average curve is small in both groups (Figure 4-8), but the value is actually almost twice as great in the fixed group (0.8 mm) as in the removable group (0.4 mm). While the mean difference between the two groups is trivial (~ 0.31 mm), the distributions show that cases with deeper curves are more likely to be fitted with a fixed retainer. Molar correction also occurs on this list (Figure 4-9). The key point is that the median for the removable group is appreciably closer to zero (closer to a Class I relationship) than the median of the fixed group, meaning that cases in 85
21 19 Total Chin (mm) 17 15 13 11 9 7 Fixed Retention Remove Figure 4-6. Box plot of “total chin” at the pretreatment examination based on type of retention. This dimension is significantly greater in the sample that would receive a fixed retainer at the end of treatment. 86
- Page 45 and 46: 4. The most stable position of the
- Page 47 and 48: CHAPTER 3. MATERIALS AND METHODS Sa
- Page 49 and 50: The present sample consisted of the
- Page 51 and 52: Figure 3-2. Illustration of how mol
- Page 53 and 54: Figure 3-3. Illustration showing di
- Page 55 and 56: Figure 3-5. Illustration showing mi
- Page 57 and 58: Figure 3-6. Illustration showing an
- Page 59 and 60: Figure 3-8. Illustration showing in
- Page 61 and 62: 34. LR3 cusp tip point. 35. Right d
- Page 63 and 64: Figure 3-10. Illustration showing o
- Page 65 and 66: Figure 3-11. Illustration of Inciso
- Page 67 and 68: 3. Go, Gonion (anatomic): The most
- Page 69 and 70: Figure 3-13. Depiction of the angle
- Page 71 and 72: Figure 3-15. Illustration of the me
- Page 73 and 74: Figure 3-17. Illustration of the me
- Page 75 and 76: Figure 3-19. Illustration of the an
- Page 77 and 78: Figure 3-21. Illustration of the up
- Page 79 and 80: Figure 3-22. Illustration of the to
- Page 81 and 82: Figure 3-24. Illustration of the po
- Page 83 and 84: the “older” Tweed force system,
- Page 85 and 86: The null hypothesis is: There was n
- Page 87 and 88: Figure 4-1. Distribution of the 166
- Page 89 and 90: occlusal issues are tolerated by bo
- Page 91 and 92: 40 35 30 FMA (degrees) 25 20 15 10
- Page 93 and 94: Figure 4-4. Plot of the average val
- Page 95: larger ANB at the recall examinatio
- Page 99 and 100: Figure 4-8. Box plot of the distrib
- Page 101 and 102: which a Class I relationship was no
- Page 103 and 104: Figure 4-11. Plot of mean Curve of
- Page 105 and 106: Figure 4-13. Box plot of the distri
- Page 107 and 108: Table A-4 addresses the question of
- Page 109 and 110: Figure 4-16. Bar chart of the avera
- Page 111 and 112: only sample changed significantly m
- Page 113 and 114: 3 2 1 0 Canonical Variate 2 -1 -2 R
- Page 115 and 116: 8 Anterior Discrepancy (ADisc) 6 4
- Page 117 and 118: 40 Incisor Aspect Ratio (IAR) 30 20
- Page 119 and 120: 1.5 Incisor Segment Depth (ISD) 1 0
- Page 121 and 122: more stable (i.e., the mean change
- Page 123 and 124: Molar Correction (MC) 10 8 6 4 2 0
- Page 125 and 126: Anterior Segment Width (ASW) 1 0 -1
- Page 127 and 128: final vertical positions. This phas
- Page 129 and 130: decreased in both arches during the
- Page 131 and 132: Figure 5-1. Plot of average Incisor
- Page 133 and 134: Based on the present results, the u
- Page 135 and 136: these variables indicate more anter
- Page 137 and 138: and the hassle associated with plac
- Page 139 and 140: Figure 5-2. Scatter-plot graph refl
- Page 141 and 142: stability?” and “for how long?
- Page 143 and 144: About two-thirds (64%) of the corre
- Page 145 and 146: Baume LJ, Horowitz HS, Summers CJ,
21<br />
19<br />
Total Chin (mm)<br />
17<br />
15<br />
13<br />
11<br />
9<br />
7<br />
Fixed<br />
Retention<br />
Remove<br />
Figure 4-6. Box plot of “total chin” at the pretreatment examination based on<br />
type of retention.<br />
This dimension is significantly greater in the sample that would receive a fixed<br />
retainer at the end of treatment.<br />
86
Change language